EP 1 247 640 B1 describes a device for sorting out tablets from a rotary tablet press, whereby a nozzle via a line and a controllable valve disposed in the line is adapted to be connected to a pressure source in order to route a tablet into a reject duct. Between the orifice of the nozzle and the valve is arranged a pressure sensor that delivers a sensor signal if the valve is opened or a predetermined minimum pressure prevails in the line. An error signal is produced, if no sensor signal is detected, when the valve is controlled to open. In this way, the opening of the valve may be monitored. However, if the orifice of the nozzle is choked up, the pressure sensor will also deliver a sensor signal, when the valve is opened, and consequently this malfunction will not be detected by the device.